The present disclosure relates to thermoplastic polycarbonate compositions that have increased flame retardance. Also disclosed are methods for preparing and/or using the same.
Polycarbonates (PC) are synthetic thermoplastic resins derived from bisphenols and phosgenes, or their derivatives. They are linear polyesters of carbonic acid and can be formed from dihydroxy compounds and carbonate diesters, or by ester interchange. Polymerization may be in aqueous, interfacial, or in nonaqueous solution. Polycarbonates are a useful class of polymers having many desired properties. They are highly regarded for optical clarity and enhanced impact resistance and ductility at room temperature or below.
However, polycarbonate polymers are not inherently non-flammable. It is thus typically necessary to include flame retardant additives, such as halogenated or non-halogenated additives, that retard the flammability of the resin and/or reduce dripping. Halogenated flame retardants containing bromide and/or chloride are increasingly subject to regulatory restrictions. Non-halogenated alternatives, including various fillers, phosphorous-containing compounds, and certain salts, have been used. However, it has been difficult to meet strict flame retardance standards using these non-halogenated alternatives, particularly in thin wall samples.
There remains a need in the art for thermoplastic polycarbonate compositions having improved heat resistance. Desirable features of such materials include, among others, excellent mechanical properties and ease of manufacture.